Eyedropper
Reference
Mode:
Draw Mode
Tool:
Toolbar ‣ Eyedropper
The Eyedropper tool is used to create materials or palette color based on sampled colors in the 3D Viewport.
Tool Settings
Material:
Create a new material with the Stroke Base Color to be the sampled color.
Palette:
Add a new color to the color palette based on the sampled color.
Usage
LMB Create a stroke material.
Shift-LMB Create a fill material.
Shift-Ctrl-LMB Create both a stroke and fill material.